Sileshi Semaw received his Ph.D. in Anthropology from Rutgers University (NJ, USA) in 1997. He worked as a Research Scientist at the Stone Age Institute, Indiana University (USA) until 2011. Subsequently, he joined the National Research Center for Human Evolution (CENIEH), in Burgos, Spain where he is currently working as a Senior Research Scientist. Semaw is CO-Director of the Gona Palaeoanthropological Research Project, and he is leading an international multidisciplinary field excavation in Ethiopia. Gona contains ancient deposits stretching back to 6.0 million years ago (Ma), and numerous sites have produced a large number of fossil hominins from key time intervals in human evolution. Semaw is trained as a Palaeolithic Archaeologist and he is undertaking lithic studies on the earliest Oldowan, the Acheulian and the Middle Stone Age. The multi-component research (paleontology, geology, taphonomy, etc.) at Gona is focused on the study of the behavioural and biological evolution of ancestral humans for the past six million years.